bobby has 24 pizza slices
he divided them among his friends and each friend got 3 pieces
how many friends did he have
so
24 divided by number of friends=3
24/y=3
multiply both sides by y
24y/y=3y
24 times y/y=3y
24 times 1=3y
24=3y
divide both sides by 3
24/3=3y/3
8=3/3y
8=1y
y=8
8 friends